The disclosure relates to a resin composition comprising poly(arylene ether). More particularly, it relates to a resin composition that is suitable for wire and cable covering material as it excels in fire retardancy without the use of halogenated compounds and chemical resistance.
Generally, amorphous resins excel in dimensional precision at the time of injection molding because of amorphous structural characteristics, and taking advantage of this characteristic, it is widely used in for molding large objects because assembly with precision is required. However, amorphous resins generally have weak chemical resistance and are easily attacked by oil, organic solvent and like.
On the other hand, crystalline resins have outstanding chemical resistance and are used in applications where the article is exposed to oil, or organic solvent etc. Generally crystalline resins are not suitable for molding large size objects because of the low dimensional precision due to molding shrinkage phenomenon associated with crystallization. Although inorganic fillers, such as glass fiber, can be added to improve molding, these composite materials may exhibit defects like warpage or deformation due to variations in shrinkage.
Poly(arylene ether) resin is an amorphous thermoplastic resin with well balanced mechanical properties, outstanding electrical properties, low water-absorbing property and excellent dimensional resistance. Moreover, poly(arylene ether) resin is compatible with polystyrene resin, which is also a non-crystalline thermoplastic resin, and can be modified easily. Resin compositions comprising poly(arylene ether) resin and polystyrene resin typically have outstanding molding processing characteristics and impact resistance, and are widely used for automobile parts, electrical and electronic components. However, as mentioned above, poly(arylene ether)/ polystyrene resin compositions are amorphous and have moderate chemical resistance at best, especially resistance to aromatic hydrocarbon solvents, e.g. if solvent is exposed to a part which is distorted or a part with residual strain, a glaze or crack may occur and may lead to the rupturing of the part or its components. Therefore, it is generally believed that poly(arylene ether)/ polystyrene resin compositions are unsuitable for applications with a possibility of exposure to lubricating oil, grease, cleaner, cooking oil, oily smoke, organic gas, and the like.
Although various experiments have been performed with poly(arylene ether)/polystyrene resin compositions in order to improve chemical resistance without negatively affecting the desirable characteristics of the composition, the technology to improve the chemical resistance has not been obtained. For example, it has been proposed to blend poly(arylene ether)/polystyrene resin compositions with a crystalline resin, such as polyolefin (e.g. polyethylene, polypropylene, EEA), polyester, nylon etc.; low molecular weight olefin series (e.g. polybutene, ethylene oligomer etc.); and rubber type polymer (e.g. SEBS, SBS, SEPS rubber etc.). However, in this technology, addition of a small amount provides a small improvement in chemical resistance, and the addition of larger amounts to a demonstrate a practical level of chemical resistance affects the mechanical strength, dimensional stability, fire retardancy, and/or causes delamination of the molded part.
Moreover, PVC resin is the conventionally used resin composition for wire and cable covering material. However PVC resin has low heat resistance temperature (60° C.), and contains halogen. Halogen containing resin compositions are increasingly undesirable.
Accordingly, there is a need for a resin composition for wire and cable covering material, which is excellent in fire retardancy (without the use of halogens), excels in chemical resistance, and has excellent compatibility, processability, heat resistance, impact resistance and flexibility.